Siding is used on houses to protect the exterior of the house and may typically be made of wood, aluminum or vinyl material. When the exterior of a house is initially made of wood, it may later also be covered with aluminum or vinyl siding secured to the wood. Trim panels are required at windows, doors and corners of the house to cover and protect the ends of the siding at these locations.
House trim panels for use with siding have been disclosed by applicant in U.S. Pat. No. 4,389,824 and in U.S. patent application Ser. No. 333,461 filed Apr. 5, 1989.
The trim panels disclosed in U.S. Pat. No. 4,389,824 comprise a receiving strip which is attached to an inner side wall of a window or door casing, and an L-shaped facing strip which is fitted around the casing front corner and over the siding ends. The receiving strip has a folded receiving slot which receives and holds the rear edge region of one leg of the facing strip along the inner casing wall and biases the other leg of the facing strip against the external siding wall.
In U.S. patent application Ser. No. 333,461, there is disclosed a similar receiving strip and facing strip combination in which the receiving strip may be attached to the front exterior casing wall rather than the inner side casing wall, thereby facilitating the nailing of the receiving strip and permitting its use where the window or door is mounted flush with the front wall. The outer hem region of the facing strip overlying the siding is also folded outwardly into an integral decorative hem trim strip and is secured against the siding by L-shaped hooks previously screwed into the house and thereafter inserted and turned to snap lock within the folds of this integral hem strip.
However, although this decorative hem construction both improves the appearance of the strip panels and results in a stronger and more permanent installation, the use of pre-screwed L-hooks inserted and turned within the folds of the hem strip is time consuming and may cause registration problems. In addition, it is difficult to consistently produce a tight water-shedding engagement of the facing strip hem against the siding.
U.S. Pat. No. 4,281,481 discloses a two-piece frame assembly, in which a door trim includes a facing strip and a C-shaped hem strip which is snapped over the outwardly projecting flanges provided on the facing strip, in order to conceal heads of the fasteners nailed into the panel of the door. Such trim assemblies are, however, not suitable for window and door trims used with siding panels which are subject to expansion and buckling due to heat.